Cutting machine



' P. S. MITTS AND W. J. WINSTON.

CUTTING MACHINE. APPUCATION FILED 050.2]. 1921.

Patented July 25, 1922.

2 SHEETSSHEET I. Q

P. S. MITTS AND W. J. WINSTON.

CUTTING MACHINE. APPLICATION FILED 050.21, 1921.

1,423,867, Patented July 192? 2 SHEETS- T 2.

AITTORNEY o stares PATENT curios.

PHILIP S. MIT'IS AND WILLIAM J. WINSTON, OF SAGINAW, MICHIGAN, ASSIGNORS '10 MI'ITS & MERRILL, OF SAGINAW, MICHIGAN, A CORPORATION OF MICHIGAN.

CUTTING MACHINE.

Patented July 25, 1922.

Application filed December 2'7, 1921. Serial No. 525,204.

T 0 all whom it may concern:

Be it known that we, PHILIP S. Mrr'rs and WILLIAM J. WINSTON, citizens of the United States, both residing at Saginaw, in the county of Saginaw and State of Michigan, have invented certain new and useful Improvements in Cutting Machines; and we do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to cutting machines and pertains more particularly to chip cutters, such as are used for cutting bark, wood and other substances into fine pieces.

Our improvement pertains more particularly to that type of cuttingmachines which comprises a revolvable cylindrical drum fitted with cutting knives and disposed with its axis horizontal and mounted in a casing.

The casing is usually provided around its periphery with stationaryanvil knives and has at one side of the axis an,inlet hopper and at the other side an outlet spout.-

In carrying out our present improvement we incorporate in a cutting machine of the type above described an improved construction and arrangement of parts whereby the effectiveness and thoroughness of cutting are improved and a more uniform product is obtained, especially where the machine, is used for fine cutting, and also eliminating liability of binding .on account of the material becoming packed between the drum and easing. By providing means for preventing friction and end-binding of thedrum we reduce the power required to operate the machine and also reduce fire risk.

In carrying out our present invention we provide means whereby the material in its passage through the machine is kept confined in the channel in which it should properly travel, namely, the space between the shell of the casing and the outer cylindrical surface of the cutting drum.

I-Ieretofore a quite serious objection to cutting machines of the type first above described has been that the drum has usually been so arranged with respect to the casing that more or less partially cut material has been permitted to depart from its proper channel, and having been squeezed around past the edge of the drum rim, travels across the end of the drum and into the outlet spout, without encountering the later stationary knives of the series. The material obviously should be cut and recut by the successive stationary knives in its passage from the inlet around the lower periphery of the casing and thence to the outlet. During this operation the material should be traveling at a very high speed, say, about seven thousand feet per minute, and since it is also under great pressure, the partially cut material consequently tends, as above explained, to squeeze out between the rim of the drum and the wall of the casing, sometimes filling the drum, and then by-passing across the end of the drum, so that the material so misses'the later stationary knives of the series and gets through without being properly cut.

To overcome this difficulty we provide a pair of retaining walls which preferably form part of the casing, one wall being located at each side of the casing and extending from the inlet around the interior of the casing to the outlet, there being just sufficient space between the two walls to receive the length of the drum rim. 7 By providing the casingwith these retaining walls at each side the material is forced to travel through the channel between the shell and the drum and can not be squeezed out around and be by-passed into the outlet spout as heretofore, regardless of the pressure to which the material may be subjected during its passage through the knives.

We furthermore provide a scraping device carried by the rim of the drum and adapted to prevent accumulation of material between the ends of the rim and the faces of the retaining walls.

With the foregoing and certain other objects in view which will appear later in the specification, our invention comprises the devices described and claimed and the equivalents thereof.

In the drawings, Fig. 1 is a vertical cross sectional view, partly broken away, showing a cutting machine embodying our improvement.

Fig. 2 is an axial section of the same.

Fig. 3 is an enlarged sectional detail showing the scraper on the end of the drum.

ig. 4 is a top plan view of a preferred form of end scraper for the drum.

Fig. 5 is a side elevation of the same.

by-passed the ends of the drum Fig. 6 is a horizontal section of the casing on reduced scale, showing diagrammatically the location of the side retaining walls.

Fig. 7 s a part vertical section on line 77 of Fig. 6.

Fig. 8 is a sectional line 8-8 of Fig. 7.

As is clearly shown in the drawings, the usual cylindrical drum 1, carrying cutting knives 2, is revolubly mounted in the casso that the drum knite edges coop; erate in the usual manner with the stationary knives 4 when the drum is rotated.

Material fed into the inlet hopper 5 passes around the lower periphery of the drum, between the drum knives and stationary knives and thence up and out through the outlet spout 6; Around the lower periphery of the drum 1, its end edges 7 travel close to a pair of retaining walls 8, 8. These walls extend frcm the inlet 5 around the lower interior of thecasing 1 to the outlet spout 6. As shown diagrammatically in Fig. 8, the distance between the said walls 8,8 isfonly slightly greater than the length 10 of the drum and the width 6*, the'outlet 6, at the end 8 of the wall 8, is greater than the distance 9 hetween said walls. Thus, as indicated by the dotted lines in Fig. 7, the edges 7 of the drum rim travel close between the retaining walls 8, 8, from the inlet 5 around to'the point 8 where the drum leaves the space between the walls and enters, a s at (tithe: wider open throat of the outlet spout It will thus be evident that duringthe passage of the material from inlet 5 around to outletspout 6, the ends 7, 7 of the drum travel very close to the respective walls 8, S and that the material being cut can not work out of the cutting channel, nor by squeezing around the ends of the drum ring, get inside the drum. i I i i It will also be observed that when the drum rim leaves the space between theretaining walls, as at 8 in Figs. and @the lower periphery of the drum travels into the wider space or throat (5 of the spout 6, so that the material as it leaves the cutting channel isimmediately thrown a space of greater width than the-channel; In a ddition, dust accumulating in the drum is free to escape from the drum at this point, so that clogging of the drum. by dust accumulation can not occur. r

Although we have forpurposes ofillustration shown a considerable clearance between the drum end 7 andthe walls 8, as in- Figs. 2, 3, 6 and 8, it will be understood that in side elevation on the practice the clearance is only suflicienttoim sure'good running conditions without a'flfording an opportunity for the niateria l to squeeze out from the cutting channel, past the end of the drum and into the outlet spout, without being properly cut. I

To prevent the building up or packing of fine material, such as dust, in this small clearance space, we provide asuitable scraper. This scraper is carried by the rim of the drum and projects not only radially outward tom the periphery, but also lengthwise the drum, or in axial direction, as illustrated in Figs. 3 and 4 where 11 is a channel or recess formed in the periphery of the drum 1 and 12 is a: square bolt head received in the recess, the bolt being fastened on the insideof the drum rim by nut 13. The recess 11 is preferably skewed with respect to theaxis o fthe drum, so that the advancing edge 14 will be relievedais at 15 after the manner of a sawtooth. Thusthe bolt head 12 may be turned to present any one of four side faces asa scraper or cutter to prevent the accumulation of material and'consequent friction between the drum rim 7 and the retaining wall 8. The top fiat face otthe bolt head. also presents four cutting edges. any one of which may be set to operate on' theouterfperiphery of the drum, so that the bolt head performs the functions not only of a circumferential cutter or'scraper, but also a lateral scraper, as shown in Fig. 3.

' y the means above described we have p-roduceda siihple and relatively inexpensive additi'oirto the cr itting'machine of ordinary @tnstractibn, whereby'all material is obliged totravel' through a thin channel from the inlet to-the outlet, the channel extending around the lower periphery of the drum bringing the "material successively into con tact with the several stationary knives.

D'uringtlie latter part of its travel through the cutting channel the material will be moving slightly upward against gravity and consequently will tend to remain better in Contact with the knives, resulting in the pro auction of material of unusually uniform fineness. The principle of operation of the machine is to confine the material to its cutting chan nel. Th'e scrapers eliminate friction that would otherwise be caused. by packing ott'the material, and the widening of the discharge spout at its throat allows free discharge from inside the cylinder, of dust and very fine particles that accumulate in the cylinder Y and might otherwise clog it.

Having thus describedour invention, what we claim and desire to secure by Letters Patent is:

1. In a cutting'machine including a casing having a knife-carrying drum rotatably mounted'therein, stationary knives disposed around the lower periphery of the casing, an inlet at ene side of the casing, and an outlet atithe epposite'sid e of the casing, a lateral ie'taining'wall ate'aclr side of said casing. said. wall'eXtendin'g from the inlet with the interior ot the casingto the outlet. the distance between said walls slightly greater than the length of said drum, a scraping device carried by the rim or said drum and adapted to prevent material packing between the end of said rim and the face of said retaining wall.

'2. In a cutting machine including a casing having a knife-carrying drum rotatably mounted therein, stationary knives disposed around the lower periphery of the casing, an inlet at one side of the casing, and an outlet at the opposite side of the casing, a lateral retaining wall at each side of said casing, said wall extending from the inlet around the interior of the casing to the outlet, the distance between said walls slightly greater than the length of said drum, the width of the outlet at the ends of said walls greater than the distance between said walls, a scraping device carried by the rim of said drum and adapted to prevent the packing of material between the end of said rim and the face or said retaining wall.

3. In a cutting machine of the class described, including a casing, stationary cutting knives disposed around the lower periphery of the casing, a rotatable knife-carrying drum, a lateral retaining wall at each side of said casing close to the end of said drum, overlapping said end and extending from the inlet around the lower part of the interior of the casing and up to the outlet, said drum closely received between said walls, and scraping devices removably secured to and projecting longitudinally beyond the rim of said drum and adapted to remove accumulations from the faces of said walls.

4:. In a cutting machine including a casing having a knife-carrying drum rotatably mounted therein, stationary knives disposed around the lower periphery of the casing, an inlet at one side of the casing, and an outlet: at the opposite side of the casing, a lateral retaining wall at each side of said casing, said wall extending from the inlet around the interior of the casing to the outlet, the distance between said walls slightly greater than the length of said drum.

In testimony whereof, we affix our signatures.

[PHILIP S. MITTS. WILLIAM J. WINSTON, 

